1. Field of the Invention
Techniques for generating timelines and event logs from one or more fixed-position cameras based on the identification of activity in the video, an assessment of the importance of the activity, the creation of a timeline identifying events of interest, and interaction techniques for seeing more details of an event or alternate views of the video are identified.
2. Description of the Related Art
Identifying events of interest within a set of synchronized video streams, such as video from a set of security cameras, is difficult due to the quantity of video and the lack of authored metadata or indexing. Yet, security personnel need to identify, either in real time or after the fact, activities of interest and determine interrelationships between activities in different video streams. They must develop an understanding of the sequence of actions that led to or happened after a particular incident.
Timelines have been explored by a variety of researchers. Plaisant et al. use timelines to visualize events in people's lives (e.g., criminal or medical records), Plaisant C., Milash B., Rose A., Widoff S., Shneiderman B., LifeLines: Visualizing Personal Histories. Proceedings of the SIGCHI conference on Human factors in computing systems, pp. 221-227, 1996. Kumar et al. visualize data from digital libraries such as information about music composers in timelines. Kumar V., Furuta R., Allen R. B., Metadata Visualization for Digital Libraries: Interactive Timeline Editing and Review. Proceedings of the third ACM conference on Digital libraries, pp. 126-133, 1998.
Other approaches are given in Chueng, S.-C. S. and Kamath C. Robust Techniques for Background Subtraction in Urban Traffic Video. Video Communications and Image Processing, SPIE Electronic Imaging, San Jose, 2004.
U.S. Pat. No. 6,366,296 discloses a timeline view for a single camera. U.S. patent application Ser. No. 10/126,555 Publication Number 20030197731 shows a related map technique where keyframes of events fade in and out while the user moves along the timeline.